I'm new to SH so can someone quickly tell me whether i can use a standard fertiliser or whether i need a hydroponic one? (ie: with Calcium). Can't seem to find out on Ray's wonderful info page.
The use of added-calcium fertilizer is to compensate for shortcomings in the fertigation solution - that is, if there's not enough in your water supply, so a "normal" fertilizer is usually adequate.
If you are used to adding oyster shell or the like as a supplement to your "regular" media, you won't want to do that with s/h, so definitely use a fertilizer with more in it.